﻿//https://leetcode.cn/problems/merge-two-sorted-lists/?envType=study-plan-v2&envId=top-100-liked

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* mergeTwoLists(ListNode* list1, ListNode* list2)
    {
        if (list1 == nullptr) return list2;
        if (list2 == nullptr) return list1;

        if (list1->val < list2->val)
        {
            list1->next = mergeTwoLists(list1->next, list2);
            return list1;
        }

        else
        {
            list2->next = mergeTwoLists(list1, list2->next);
            return list2;
        }

    }
};